1. Field of the Invention
This invention relates to a dental detection apparatus for locating the position of the final end (root apex) of a root canal by means of determining the impedance variations between a reamer and a single electrode interval during dental treatment of root canals by dentists.
More specifically, the dental detection apparatus for locating the position of a root apex, of the present invention, is based on providing an alternating current with two different frequencies between a reamer inserted in the root canal and a single electrode contacting the mucosa of the patients buccal cavity, and thereafter obtaining the corresponding impedances to the two frequency signals as the reamer approaches the root apex in order to detect the position of the root apex by measuring the difference between these impedance variations.
2. Description of the Prior Art
The dental detection apparatus for locating the position of a root apex according to the invention is based upon on the difference of the impedance variations corresponding to two different frequency signals in order to accurately detect the position of the root apex, even though the internal portion of the root canal is wet, or a nerve is left in the internal portion of the root canal and sanious pus is present.
Prior art devices of the type shown in FIG. 1 however, detect the position of the root apex with moisture, nerve and sanious pus in the root canal, with a meter indicating the position of the root apex according to the condition of the root canal. In such devices, a reamer is inserted into the root canal, and a volume adjustment made to set the reading of the meter at a required position (standard position) while continuing insertion of the reamer.
In the prior art device shown in FIG. 1, a reamer 2 is electrically connected to a detection apparatus A and then the reamer is inserted into a root canal 10 of a tooth 1 being treated for a patient to detect the position of the root apex. An indicator N on meter M indicates the position of the root apex on apparatus A by the amount it deflects in the direction of the position described as APEX as the reamer is inserted into the root canal and the condition of the root canal is adjusted for by manipulating dial D. Adjusting the reading N to the standard position described as ADJ is made by turning the dial D of a variable resistor incorporated in the body a. Then, while manipulating dial of and observing the reading N of the meter M, the reamer 2 is inserted and the location of root apex within the root canal 10 is made. When the reading N reaches the position of APEX, thereby indicating the location of the root apex the dental treatment is stopped.
Every time the dental treatment is made with such a prior art device, the reading N of the meter M must be manipulated by dial D to be set at the standard position. This operation is a complicated procedure.